title: Childhood overweight after establishment of the gut microbiota: the role of delivery mode, pre-pregnancy weight and early administration of antibiotics.
abstract: OBJECTIVE
  To investigate whether delivery mode (vaginal versus by caesarean section), maternal pre-pregnancy body mass index (BMI) and early exposure to antibiotics (<6 months of age) influence child's risk of overweight at age 7 years, hence supporting the hypotheses that environmental factors influencing the establishment and diversity of the gut microbiota are associated with later risk of overweight.
  
  
  METHODS
  Longitudinal, prospective study with measure of exposures in infancy and follow-up at age 7 years.
  
  
  METHODS
  A total of 28 354 mother-child dyads from the Danish National Birth Cohort, with information on maternal pre-pregnancy BMI, delivery mode and antibiotic administration in infancy, were assessed. Logistic regression analyses were performed with childhood height and weight at the 7-year follow-up as outcome measures.
  
  
  RESULTS
  Delivery mode was not significantly associated with childhood overweight (odds ratio (OR):1.18, 95% confidence interval (CI): 0.95-1.47). Antibiotics during the first 6 months of life led to increased risk of overweight among children of normal weight mothers (OR: 1.54, 95% CI: 1.09-2.17) and a decreased risk of overweight among children of overweight mothers (OR: 0.54, 95% CI: 0.30-0.98). The same tendency was observed among children of obese mothers (OR: 0.85, 95% CI: 0.41-1.76).
  
  
  CONCLUSIONS
  The present cohort study revealed that a combination of early exposures, including delivery mode, maternal pre-pregnancy BMI and antibiotics in infancy, influences the risk of overweight in later childhood. This effect may potentially be explained by an impact on establishment and diversity of the microbiota.
authors.affiliation: Institute of Preventive Medicine, Copenhagen University Hospital, Øster Søgade 18, Copenhagen, Denmark. ta@ipm.regionh.dk
authors.forename: T A
authors.initials: TA
authors.lastname: Ajslev
authors.forename: C S
authors.initials: CS
authors.lastname: Andersen
authors.forename: M
authors.initials: M
authors.lastname: Gamborg
authors.forename: T I A
authors.initials: TI
authors.lastname: Sørensen
authors.forename: T
authors.initials: T
authors.lastname: Jess
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D015992:Body Mass Index; D002585:Cesarean Section / Q000009:adverse effects*; D002648:Child; D036861:Delivery, Obstetric / Q000379:methods*; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D054892:Metagenome; D009035:Mothers; D009765:Obesity / Q000209:etiology*; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents